Scientists from the Universidad Nacional de la Patagonia San Juan Bosco (UNPSJB) have determined that a complete skull and partial neck fossil discovered in Patagonia, Argentina belong to a new species of titanosaurian dinosaur: Sarmientosaurus musacchioi.
Titanosaurs are a type of sauropod that ranged in size from the weight of a cow to the largest known sperm whale. With characteristic long necks and tails, these plant-eaters are believed to have been the most common large herbivores in the Southern Hemisphere landmasses during the Cretaceous period, which took place between 145.5 and 65.5 million years ago.
Despite their large population during the this time period, scientists have had difficulty finding the skulls of these ancient animals, a critical piece of evidence for shedding light on their unique biology. Although more than 60 titanosaurs have been named, only four are represented by nearly complete or semi-complete skulls.
In the new study, the team used computerized tomography (CT) imaging to examine the skull and neck fossils of the S. musacchioi. The results revealed that the creature's brain was small in comparison to its body, much like other sauropods. However, they also revealed that their sensory capabilities were much more advanced than other sauropods, with large eyeballs, good vision and an inner ear that was likely better at detecting low-frequency airborne sounds.
The team also discovered that the new species inner ear organ possessed a balance that indicates it held its head with its snout facing downward often in order to feed on plants, conjuring up an appearance similar to well-known fictional character Eeyore.
"Discoveries like Sarmientosaurus happen once in a lifetime," said Rubén Martínez of the UNPSJB and lead author of the study. "That's why we studied the fossils so thoroughly, to learn as much about this amazing animal as we could."
The S. musacchioi is named after the town of Sarmiento in Chubut Province, which is located near the fossil discovery site. Furthermore, it also honors the late Eduardo Musacchio, a professor at the UNPSJB and friend of the researchers behind the new finding.
The findings were published in the April 26 issue of PLOS ONE.
